1. Field of the Invention
The present disclosure relates to a wiper device, and in particular, relates to a wiper device in which a wiper motor that swings a wiper back and forth includes a controller that controls the wiper motor. The present disclosure further relates to a wiper motor.
2. Related Art
In known wiper devices, a wiper motor is driven coordinated with squirting of washer fluid when a washer switch is switched ON, swinging a wiper back and forth for plural cycles. In such wiper devices, technology is known in which drive of the wiper motor begins after a specific duration has elapsed since squirting the washer fluid, and the washer fluid is sure to have landed on a glass face of a windshield that was previously in a dry state. This suppresses scratching of the glass face accompanying the wiping operation by the wiper.
Japanese Patent Application Laid-Open (JP-A) No. 2010-288283 describes a wiper motor (an electric motor with a speed reduction mechanism) configuring part of a wiper device. The wiper motor described includes a motor body configured including an armature, a speed reduction mechanism that reduces the rotation speed of the armature at a specific speed reduction ratio for transmission to an output shaft, and a control circuit that controls drive of the motor body itself. The control circuit is configured by mounting plural drive devices on a circuit board (control board). The drive devices are a source of noise, and so the drive devices are separated from a connector provided beside a worm wheel placement portion on one side of a worm gear placement portion, so as to be concentrated on the other side of the worm gear placement portion.
When the wiper swings back and forth coordinated with squirting of the washer fluid, the washer fluid landing on the glass face of the windshield is subject to centrifugal force in a direction away from the center of swing of the wiper, namely in a direction heading out of a wiping range of the wiper, accompanying the wiping operation of the wiper swinging back and forth. The centrifugal force acting on the washer fluid changes according to the wiping speed of the wiper, with the centrifugal force acting on the washer fluid increasing as the wiping speed of the wiper increases. In configurations provided with a link mechanism between the wiper motor and a wiper arm, properties of the link mechanism mean that the wiping speed of the wiper is at its greatest in the vicinity of the center between upper and lower return positions, even if the wiper motor maintains the same rotation speed.
When the vehicle is travelling, washer fluid that has landed on the glass face of the windshield is subject to a force in a direction toward an upper end portion of the windshield, due to an airflow caused by passing air. The force acting on the washer fluid from the airflow of the passing air changes according to the vehicle speed, with the force acting on the washer fluid from the airflow of the passing air increasing as the speed of the airflow caused by passing air increases with higher vehicle speed.
There is therefore an issue in that in cases in which the washer switch is switched ON when the vehicle is travelling at high speed, the amount of the washer fluid landing on the glass face of the windshield that is expelled from a wiping range of the wiper increases, and it is possible that the washer fluid in the wiping range of the wiper may become insufficient. In particular, it is possible that washer fluid could become conspicuously insufficient in a range from the vicinity of the center between the upper and lower return positions of the wiper to the upper side return position, since there is only a small difference in angle between the direction of the centrifugal force acting on the washer fluid and the direction of the force acting on the washer fluid from the airflow of the passing air.
The wiper is normally operated together with the washer. It is therefore efficient to install a wiper control circuit for controlling drive of the wiper body that drives the wiper, and a pump control circuit for controlling drive of a washer pump, in the wiper motor. However, since the wiper motor accordingly includes not only a drive device for the motor body that drives the wiper, but also a drive device that drives the washer pump provided separately to the wiper motor, wiring electrically connected to both drive devices forms an antenna, emitting noise. When the connectors and the drive devices are disposed at a distance from each other, the wiring between them becomes longer, and it becomes paramount to suppress the noise emitted from the wiper motor.
An object of the present disclosure is to obtain a wiper device capable of suppressing a lack of washer fluid in a wiping range of a wiper in cases in which a washer switch is switched ON when a vehicle is travelling at high speed.
Another object of the present disclosure is to obtain a wiper motor capable of reducing noise emission even when the wiper motor includes circuits to drive and control a wiper and a washer.